As this kind of system, a system that includes a coolant control valve for controlling passage of water to an engine body, a EGR cooler, auxiliaries, and the like, and that limits passage of coolant at cold starting has been suggested (for example, see Patent Document 1). With the above system, because circulation of coolant is stopped at starting, a warm-up of the internal combustion engine can be suitably facilitated.
Patent Document 2 describes a technique for facilitating a warm-up of a cylinder block by supplying coolant, heated at an EGR cooler by exhaust gas, to the cylinder block.
Patent Document 3 describes a technique for preventing an overheat by circulating coolant in an engine or an EGR cooler even when a water pump is stopped.